It is well known in the operation of construction machines that the nature of the terrain in which they operate does not lend itself to providing a comfortable ride for the operator of the machine. This is especially true with the large machines that place the operator quite some distance off the ground wherein the rough conditions of the ground are amplified by the distance between the ground and the operator. This not only causes the operator some discomfort, it also is very fatiguing.
In order to counteract this situation, there have been many improvements made to the operator station or cabs of these machines. One area of improvement has been the seat assembly. Many seat assemblies have been provided with various adjustments to accommodate the varying sizes of operators. One of these adjustments resides in the tilting of the back portion of the seat with respect to the base to give the operator better support, and therefore greater comfort, in the area of his back. There have been several types of reclining mechanism that have been known to work quite well in providing an acceptable range of adjustment, however many of these mechanisms inherently have a significant amount of relative movement or "play" in the mounting structure. This relative movement is also amplified by the traverse of the machine over rough terrain and has been known to be a source of discomfort.
A typical reclining mechanism uses a plurality of gears that mesh with a portion of the seat back to permit relative rotation between the seat back and the seat base. A locking pawl engages one of the gears and prevents rotation of the gears thereby fixing the location of the back portion. While this works well to lock one side of the back portion it becomes a problem to lock both sides with a single locking mechanism and yet provide a mechanical stop for both sides of the seat back. In order to do this, extraordinary locating measures must be taken in the manufacturing and the assembly of the seat to insure that the meshing between the gears of the reclining mechanism and the seat back occur without binding. These manufacturing and assembly measures are not only costly and drive up the cost of the seat, but they also require an inordinate amount of time to properly locate and adjust the position of the various components during the assembly process to insure proper operation.
The present invention is directed to overcoming one or more of the problems set forth above.